How chimpanzees (Pan troglodytes) share the spoils with collaborators and bystanders.

Maria John,Michael Tomasello,Alicia P Melis,Shona Duguid

doi:10.1371/journal.pone.0222795

Maria John, Michael Tomasello + Show 2 more

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https://doi.org/10.1371/journal.pone.0222795

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Journal: PloS one	Publication Date: Sep 23, 2019
Citations: 10	License type: CC BY 4.0

Affiliation: Duke University, University College London

Abstract

Chimpanzees hunt cooperatively in the wild, but the factors influencing food sharing after the hunt are not well understood. In an experimental study, groups of three captive chimpanzees obtained a monopolizable food resource, either via two individuals cooperating (with the third as bystander) or via one individual acting alone alongside two bystanders. The individual that obtained the resource first retained most of the food but the other two individuals attempted to obtain food from the "captor" by begging. We found the main predictor of the overall amount of food obtained by bystanders was proximity to the food at the moment it was obtained by the captor. Whether or not an individual had cooperated to obtain the food had no effect. Interestingly, however, cooperators begged more from captors than did bystanders, suggesting that they were more motivated or had a greater expectation to obtain food. These results suggest that while chimpanzee captors in cooperative hunting may not reward cooperative participation directly, cooperators may influence sharing behavior through increased begging.

Highlights

Sharing the spoils of cooperatively gained rewards is key to maintaining cooperation
The research was approved by the management, board members and veterinarian at the Chimpanzee Sanctuary and Wildlife Conservation Trust (CSWCT)
This study investigated sharing of cooperatively produced resources in semi-captive chimpanzees

Summary

Introduction

Sharing the spoils of cooperatively gained rewards is key to maintaining cooperation. Human societies often have very clear rules about how the products of collaborative hunting or foraging should be shared among the participants and the wider community [1]. Chimpanzees, one of our closest living relatives, are known to hunt in groups and share the meat amongst group members [2]. This behavior is of particular interest to understanding the evolution of human cooperation. In the following experiment we aim to investigate the factors influencing the distribution of cooperatively gained resources amongst chimpanzees. Group hunting of medium-sized mammals is widespread across chimpanzee communities.

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